scholarly journals Stable isotope composition of dissolved inorganic carbon and particulate organic carbon in sea ice from the Ross Sea, Antarctica

2010 ◽  
Vol 115 (C9) ◽  
Author(s):  
David R. Munro ◽  
Robert B. Dunbar ◽  
David A. Mucciarone ◽  
Kevin R. Arrigo ◽  
Matthew C. Long
Keyword(s):  
Stable Isotope ◽  
Organic Carbon ◽  
Sea Ice ◽  
Particulate Organic Carbon ◽  
Inorganic Carbon ◽  
Ross Sea ◽  
Dissolved Inorganic Carbon ◽  
Isotope Composition ◽  
Stable Isotope Composition

scholarly journals Particulate organic carbon (POC) in relation to other pore water carbon fractions in drained and rewetted fens in Southern Germany

2008 ◽  
Vol 5 (6) ◽  
pp. 1615-1623 ◽  
Author(s):  
S. Fiedler ◽  
B. S. Höll ◽  
A. Freibauer ◽  
K. Stahr ◽  
M. Drösler ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Pore Water ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Relative Importance ◽  
Pore Waters ◽  
Calcareous Fens ◽  
Essential Components ◽  
The Individual

Abstract. Numerous studies have dealt with carbon (C) contents in Histosols, but there are no studies quantifying the relative importance of the individual C components in pore waters. For this study, measurements were taken of all the carbon components (particulate organic carbon, POC; dissolved organic carbon, DOC; dissolved inorganic carbon, DIC; dissolved methane, CH4) in the soil pore water of calcareous fens under three different water management regimes (re-wetted, deeply and moderately drained). Pore water was collected weekly or biweekly (April 2004 to April 2006) at depths between 10 and 150 cm. The main results obtained were: (1) DIC (94–280 mg C l−1) was the main C-component. (2) POC and DOC concentrations in the pore water (14–125 mg C l−1 vs. 41–95 mg C l−1) were pari passu. (3) Dissolved CH4 was the smallest C component (0.005–0.9 mg C l−1). Interestingly, about 30% of the POM particles were colonized by microbes indicating that they are active in the internal C turnover. Certainly, both POC and DOC fractions are essential components of the C budget of peatlands. Furthermore, dissolved CO2 in all forms of DIC appears to be an important part of peatland C-balance.

scholarly journals Radiocarbon Dating of Individual Fatty Acids as a Tool for Refining Antarctic Margin Sediment Chronologies

Radiocarbon ◽  
2003 ◽  
Vol 45 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Naohiko Ohkouchi ◽  
Timothy I Eglinton ◽  
John M Hayes
Keyword(s):  
Fatty Acids ◽  
Organic Matter ◽  
Organic Carbon ◽  
Radiocarbon Dating ◽  
Inorganic Carbon ◽  
Surface Sediments ◽  
Ross Sea ◽  
Dissolved Inorganic Carbon ◽  
Accumulation Rate ◽  
Sea Surface

We have measured the radiocarbon contents of individual, solvent-extractable, short-chain (C14, C16, and C18) fatty acids isolated from Ross Sea surface sediments. The corresponding 14C ages are equivalent to that of the post-bomb dissolved inorganic carbon (DIC) reservoir. Moreover, molecular 14C variations in surficial (upper 15 cm) sediments indicate that these compounds may prove useful for reconstructing chronologies of Antarctic margin sediments containing uncertain (and potentially variable) quantities of relict organic carbon. A preliminary molecular 14C chronology suggests that the accumulation rate of relict organic matter has not changed during the last 500 14C yr. The focus of this study is to determine the validity of compound-specific 14C analysis as a technique for reconstructing chronologies of Antarctic margin sediments.

scholarly journals The relevance of particulate organic carbon (POC) for carbon composition in the pore water of drained and rewetted fens of the "Donauried" (South-Germany)

2008 ◽  
Vol 5 (3) ◽  
pp. 2049-2073
Author(s):  
S. Fiedler ◽  
B. S. Höll ◽  
A. Freibauer ◽  
K. Stahr ◽  
M. Drösler ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Pore Water ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Relative Importance ◽  
Pore Waters ◽  
Soil C ◽  
Calcareous Fen ◽  
Essential Components

Abstract. Numerous studies have dealt with carbon (C) concentrations in Histosols, but there are no studies quantifying the relative importance of all individual C components in pore waters. For this study, measurements were made of all the carbon components (i.e., particulate organic carbon, POC; dissolved organic carbon, DOC; dissolved inorganic carbon, DIC; dissolved methane, CH4) in the soil pore water of a calcareous fen under three different water management regimes (re-wetted, deeply and moderately drained). Pore water was collected weekly or biweekly (April 2004 to April 2006) at depths between 10 and 150 cm. The main results obtained were: (1) DIC (94–280 mg C l−1) was the main C-component. (2) POC and DOC concentrations in the pore water (14–125 mg C l−1 vs. 41–95 mg C l−1) were pari passu. (3) Dissolved CH4 was the smallest C component (0.005–0.9 mg C l−1). Interestingly, about 30% of the POM particles were colonized by microbes indicating that they are active in the internal C transfer in the soil profile ("C-Shuttles"). Consequently, it was concluded that POC is at least as important as DOC for internal soil C turnover. There is no reason to assume significant biochemical differences between POC and DOC as they only differ in size. Therefore, both POC and DOC fractions are essential components of C budgets of peatlands. Furthermore dissolved CO2 in all forms of DIC apparently is an important part of peatland C-balances.

scholarly journals CARBON-DISC 1.0 – A coupled, process-based model of global in-stream carbon biogeochemistry

2019 ◽  
Author(s):  
Wim Joost van Hoek ◽  
Lauriane Vilmin ◽  
Arthur H. W. Beusen ◽  
José M. Mogollón ◽  
Xiaochen Liu ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Measurement Data ◽  
River Mouth ◽  
Spatial And Temporal Variability ◽  
Time Step ◽  
C Cycle ◽  
Basin Scale

Abstract. Here, we present the implementation of the freshwater carbon (C) cycle in the Dynamic In-stream Chemistry module (CARBON-DISC), which is part of the Integrated Model to Assess the Global Environment-Dynamic Global Nutrient Model (IMAGE-DGNM). A coupled hydrology-biogeochemistry approach with 0.5 by 0.5-degree resolution accounts for the spatial and temporal variability in dynamic conditions in the aquatic continuum using independent global databases. This process-based model resolves the concentrations, transformations and transfer fluxes of dissolved inorganic carbon (DIC), dissolved organic carbon (DOC) and terrestrial and autochthonous particulate organic carbon (POC) from headwaters to river mouth with a time step of 1 month for the period 1950–2000. This is a major step forward in basin scale modelling of the C processing in freshwater systems, since simulated results can be validated at every location and point in time, and the model can be applied for retrodiction and to analyse future scenarios. Validation of the model with long-term measurement data shows a fair agreement, considering that this is a global model. To analyse the performance of the full production-respiration DISC module, two other schemes are presented, including an abiotic system excluding any in-stream processing of DOC and allochthonous production, and an extended abiotic system including heterotrophic respiration, but excluding production. Furthermore, a sensitivity analysis shows that many parameters, such as temperature, solar radiation, organic sediment mineralization rate and C inputs, including particulate organic carbon from terrestrial vegetation and dissolved inorganic carbon from groundwater, strongly affect atmosphere-freshwater exchange of CO2.

Organic carbon storage and stable isotope composition of soils along a grassland to forest environmental gradient in Saskatchewan

2003 ◽  
Vol 83 (4) ◽  
pp. 405-414 ◽  
Author(s):  
A. Landi ◽  
D. W. Anderson ◽  
A. R. Mermut
Keyword(s):  
Stable Isotope ◽  
Organic Carbon ◽  
Carbon Storage ◽  
Isotope Composition ◽  
Carbon Accumulation ◽  
Accumulation Rates ◽  
Stable Isotope Composition ◽  
Organic C ◽  
Native Prairie ◽  
Prairie Soils

Limited information is available about soil organic carbon accumulation rates and stable isotope composition in the boreal region of the Canadian prairies. The objectives of the study were to document soil development, measure carbon storage and accumulation rates, and determine the 13C/12C ratio of organic matter in native prairie soils in the major soil-climatic zones of Saskatchewan. The mean thickness of the Ah horizon increases from 5 cm in the Brown Chernozems to 14 cm in Black Chernozems, and this horizon is absent in Gray Luvisols. The thickness and degree of development of B horizons increase from Brown to Gray soils. Total organic C storage to 1.2 m depth in Brown, Dark Brown, Black Chernozems, and Gray Luvisols is 9.08, 11.72, 14.88, 9.63 kg C m-2, respectively. The long-term mean annual accumulation rates of organic C for Brown, Dark Brown, Black, and Gray soils are 0.57, 0.90, 1.18, and 0.84 g m-2 yr-1, respectively. For a Rego Black Chernozem the rate is 1.83 g m-2 yr-1. All these values are higher than those reported for temperate grasslands in the United States of America. The ỏ13C values of organic C (an average of all profiles in each soil zone to 1.2-m depth) range from -22.9 ‰ for Dry Brown soils, -24.3‰ for Brown soils, -24.8‰ for Dark Brown soils, -25.3‰ for Black soils, and -26.8‰ for Gray soils. The relative contribution of C4 plants to soil organic C decreases from the warm semiarid grassland to the moist Boreal region, where C4 plants have not influenced organic C at all. Considering the net primary production (NPP) estimated for the soil zones, average aboveground carbon sequestration is estimated to be about 0.46% of NPP. These data provides a realistic assessment of C balances in native prairie soils of Saskatchewan. Key words: Rate of carbon accumulation, stable isotope of soil carbon, soil zones of Saskatchewan, grassland soils, forest soils, Rego Black Chernozem soils

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